The wireless distribution of broadband signals within a building is becoming commonplace. Wi-Fi is now the most common way people access the Internet. Smart phones compliant with 3G and 4G standards are commonly used inside buildings. Personal computers, laptop computers, smart phones, tablet computers, PDAs and other portable devices are typically configured to receive a wireless broadband signal. In addition, televisions, DVD players, Blu-ray disc players, smart thermostats, printers, copiers and many other digitally enabled home or business appliances are configured for wireless network access. To meet the needs of these and similar devices, many buildings now include a wireless access point (WAP), base station or repeater connected to a wired data or communication network to send and receive data or communication signals from the wired network to wireless devices within or near the building.
One problem with the transmission of wireless broadband signals within a building is difficulty obtaining a sufficiently strong communication channel between the WAP or repeater and various receiving devices. For example, the exceptionally popular Wi-Fi standard defined in IEEE 802.11b is a low powered solution (less than 1 W) having a range of no more than 300 feet from the transmitter. The closer a receiving device is to the transmitter the better chance the receiver will have of connecting and typically the faster the Wi-Fi uplink/downlink performance will be. Connectivity and signal strength problems can be exacerbated by the walls, floors, ceilings and other surfaces or barriers present in a typical building which can cause signal attenuation and reflection.
Wireless broadband signals are transmitted according to an IEEE standard such as the 802.11a/b/g/n, 802.11ac/ad, LTE, LTE Advanced or WiMAX 802.16d/e standards. These standards in many instances require a broadband signal having multiple orthogonal subcarriers. For example, a signal may be communicated in Orthogonal Frequency Division Modulation (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) format. Signals having multiple orthogonal subcarriers are well-suited to multiuser access. Each user communicates with the WAP or repeater over a set of dedicated or time-allocated sub channels depending upon the signal format used. Accordingly, it is desirable to intelligently allocate subchannels to various users. Intelligent allocation provides each user with dedicated or time-allocated sub channels having sufficient signal strength and signal-to-noise ratio for high-quality communication.
U.S. Pat. No. 6,980,768 teaches the use of a building ventilation system as a waveguide to enhance the distribution of a spread spectrum signal within a building, in particular a code division multiple access (CDMA) telecommunications signal. The U.S. Pat. No. 6,980,768 describes how the ducts of a conventional ventilation system can operate as wave guides. Bends, kinks, rough surfaces, splits, and variations in duct size or configuration will inevitably cause fading in any RF signal transmitted through a duct waveguide. The spread spectrum nature of the signal described in the U.S. Pat. No. 6,980,768 provides little opportunity for transmission optimization within a ventilation system. In addition, CDMA signals do not have multiple orthogonal subcarriers. Therefore, there is no opportunity or need to address the optimization of subcarrier allocation. Hence, there is a need for solutions that can overcome some or all of the technical hurdles identified above to allow the effective distribution of broadband wireless signals having multiple orthogonal subcarriers in a building.